As an Aesthetician that has tried everything from snail mucus to goats milk, and everything in-between, it still comes down to science and research. I am asked the question every day, "why should I spend money on expensive Spa products, when I can get some of the same stuff at (fill in the blank) store/counter? My response is always, you truly get what you pay for. Not that all of these products are bad for your skin, they most likely would not be on the shelf if they were. However, professional, medical grade products are rigorously tested, researched, have numerous clinical studies and years of research and data providing that they actually "work", prior to being allowed to be sold.
Over the counter products do not have to have studies conducted or even years of research backing the formulation. OTC products are only allowed to penetrate the surface of the skin and cannot address skin's deeper concerns, like acne, pigment disorders and wrinkles. OTC products sit on top of the skin's surface, and will not change the skin's condition at the dermal level like a medical grade product. Medical grade products have the science behind them to have a delivery system to actually make a change at the dermal level. Medical-grade products are specifically designed with advanced delivery methods and technologies that have the capabilities to penetrate deep down to heal and make changes to your skin condition. So if you're going to spend money on your only face, then it is truly worth the investment.